Poor physical quality - the display is hard to read, much harder than their two line $12 calculator. The plastic is very cheap and poorly finished. I got this new for $45 with teacher discount and its being returned the next day. Casio graphing is much better physical quality and has superior finance built in as well. I am sure the calculus part of this is great... but if its not well made or easy to read its a waste of money. HPs origin was calculators, now they are are the bottom of the heap. This is a review but there seems not way for me to create one.